Twins, quadratures and syzygies have long been part of Nigerian literature and myth, usually as a challenge to views of society based on the primacy of the individual. Given the way the country has gone, Nigeria now being a byword for scheming selfishness and corruption, it seems no accident that twins should play such a big role in the late renaissance of the Nigerian novel, as illuminated by Helon Habila, Chimamanda Ngozi Adichie and Helen Oyeyemi.

That renaissance is a phenomenon for which any lover of African literature must be grateful, for not since the early 1970s has much emerged from the continent that has been able to make a global impact. There are many reasons for this, but chief among them is the paralysing connection between a breakdown of societal mechanisms (including publishing) and the wider degradation of what might be described as "citizenship memory" - something by no means limited to Africa.

Oyeyemi's beguiling novel The Icarus Girl dealt with relationships between twins and doubles as a way into cultural difference. Twins also feature in Adichie's exceptional Half of a Yellow Sun, as do themes of religion, tribal loyalty and education in exactly the type of civic renovation with which the younger generation of Nigerian novelists have tasked themselves. It is a hard ideal but a crucial one, for civil society can only be re-established in Africa through a proper understanding of history.

Habila, Caine prizewinner and author of the acclaimed Waiting for an Angel, has also written a novel in which twins and history are central. It is a very subtle piece of work in which the story of a family and community in northern Nigeria in the 1980s and early 90s is woven into a wider sociopolitical narrative, touching on education, responsibility, the colonial inheritance and the mythic substratum of folklore.

Habila's twins, Mamo and LaMamo, have nearly the same name, but are very different characters. Mamo is an awkward invalid (he has sickle-cell anaemia), whereas LaMamo is strong and bold. Having lost their mother in childbirth, they are unified only in hatred of their father, Lemang, a selfish lothario who pays them scant attention. By way of revenge they put scorpions in the shoes of this failed parent, who stands allegorically for years of failed national leaders.

After a strange scene in which the twins murder a witch's dog, rubbing rheum from its eyes into their own to enable them to see ghosts, they decide to run away and join the army - only for Mamo, suffering an anaemic crisis, to turn tail. He will not see his brother for 20-odd years, though letters tell of time spent fighting in various mercenary armies in Chad, Mali and Liberia.

Mamo becomes a local historian and schoolteacher, all the while struggling with his father and his illness. Lemang is transformed into a wealthy businessman and politician. His star rises high until his plan to bring water to the dusty land by a process called "reverse osmosis" is stolen by a rival. Mamo's school becomes an electoral pawn. Done as high farce, these scenes of political infighting are very amusing, but the serious burden - nothing less than the future of a country - is always booming away in the background.

Chosen by the waziri (vizier) of the local mai, or emir, to write a history of the mai's rule and family, Mamo's own fortunes rise as his father's decline. He has a passionate love affair with a woman called Zara, who, in another parallel, also wants to be a writer, and settles into a new life as the mai's secretary. But things are not what they seem, and Mamo realises he must foil the wily waziri's schemes.

Readers will remember the scheming Sam Adekunle in William Boyd's A Good Man in Africa, drawn from the wonderful waziri in Joyce Cary's 1939 novel Mister Johnson, which Boyd adapted for the screen. What is exciting about Habila is that he combines these western literary archetypes with a much older, oracular style of African tale-telling in which the novel becomes part of the oral narrative tapestry of a particular community. The book also integrates many themes of the modern African novel, from the journey undertaken by LaMamo as a version of the traditional initiatory excursion, to the equivalent quest of the hero, Mamo, for true wisdom.

Measuring Time is both a historical novel that "measures time" in the sense of comparing historical periods, and a psychological study of a man who must "measure up" to his brother and the critical demands of a society in crisis. Most importantly of all, however, it is a triumphant celebration of relativism. By the end, in spite of abounding tragedies, Mamo has discovered that the secret of survival lies not in individualism but in exactly the sort of oscillatory in-between-ness that his twinship exemplifies.

· The film of Giles Foden's novel The Last King of Scotland is currently on nationwide release